The present invention relates to a remotely actuated splitter bypass system and method for testing and maintaining a copper loop. More particularly, the present invention is directed to a system and method for remotely actuating a bypass function in a splitter such that testing and maintenance can be performed by a local exchange carrier without interference to/from the plain old telephone system (POTS) service. In particular, the present invention discloses systems and methods allowing a competitive local exchange carrier (CLEC) to access the copper loop for testing and maintenance with minimal interference to/from the POTS service.
In 1999, the Federal Communications Commission (FCC) adopted rules to promote competition between local telephone companies and providers of high speed Internet access and other data services by directing the telephone companies to share their telephone lines with such providers. With these rules, many companies can deploy new technologies on a faster, more cost-effective basis, thereby allowing residential and business customers to access broadband and POTS services from a choice of different providers.
Digital Subscriber Line or xDSL is one of the most promising new technologies for delivering superior service and higher speed connections over existing infrastructure. Recent changes in the telecommunications industry such as the deregulation of local markets have brought on the emergence of new technologies such as xDSL. In addition, the growing demand for faster, more reliable Internet access has increased the demand for technologies that deliver higher speed connections over existing infrastructure.
As known, different competing forms of digital subscriber line technologies are collectively designated as xDSL technologies with the xe2x80x9cxxe2x80x9d representing various one or more letter combinations, which are used in front of the xe2x80x9cDSLxe2x80x9d acronym to designate the type of technology being used. Some of the more prevalent xDSL technologies include HDSL, ADSL, SDSL, RADSL, VADSL, and VDSL.
xDSL uses the existing copper loop that is traditionally used for conventional telephony to deliver data at high bandwidth. Currently, the transmission rates for xDSL technologies are dependent on the distance between a central office and a particular customer. Depending on the type of xDSL technology, the transmission rate downstream to the customer and upstream to the central office may vary. Also, xDSL uses packet switching technology that operates independently of the voice telephone system, allowing telephone companies to provide Internet service and not lock up circuits for telephone calls. xDSL can carry both voice and data signals simultaneously, in both directions, allowing the customer to log onto the Internet and make a telephone call at the same time. Thus, it is easy to understand why xDSL is becoming the preferred system and method for sending/receiving analog and digital data/signals in the telecommunications industry.
Traditionally, incumbent local exchange carriers (ILECs) used the existing copper loop for voice telephone and data services. With the adoption of the new FCC rules, competitive local exchange carriers (CLECs) can obtain access to the high-frequency portion of the local loop from the ILECs. This enables the CLECs to provide xDSL services over the same telephone lines simultaneously used by the ILECs, which technique is know as xe2x80x9cline sharing.xe2x80x9d
Line sharing allows customers to obtain data service from either the ILEC or CLEC without having to forego the traditional voice service from their current provider. Line sharing also allows customers to receive both voice and data services on the same line; thus, eliminating the need for customers to procure a second line. In other words, line sharing involves the CLEC providing xDSL service on the same copper loop on which the ILEC provides POTS service. As a result, this allows for a more efficient use of the existing telephone infrastructure by allowing CLECs to take advantage of the large installation base that already exists.
One major shortcoming of the current line sharing system and method is the testing and maintenance of the copper loop for the CLECs. This problem is better understood by describing the current line sharing system and method, which is described in greater detail with reference to FIGS. 1-2.
FIG. 1 illustrates a simplified diagram of a conventional line sharing system. In the conventional system, a central office (CO) is connected to a customer""s telephone 16 and an ATU-R (ADSL transceiver remote unit) 18 or similar end unit at the customer""s premise (home, office, etc.) using a copper loop 14 (pair of copper wires). In the CO, a voice switch 2, which is generally owned by the ILEC, and a DSLAM (DSL Access Multiplexers) 4, which in this case is owned by the CLEC, are connected to a CO splitter 6. As known, the voice switch 2 includes circuitry for providing POTS (voice) service and the DSLAM 4 includes circuitry for providing xDSL service to the customer. The DSLAM 4 generally receives incoming xDSL lines and aggregates the traffic onto high-speed uplink trunks such as ATM or Frame Relay. The CO splitter 6 is typically found in a main distribution frame and is generally a passive unit (i.e., no power).
In greater detail, the CO splitter 6 is used to isolate the voice service from the xDSL service. The isolation generated by the CO splitter 6 is important for minimizing interference between the two types of services and removing transients. The CO splitter 6 separates voice and data band signals received from the copper loop 14 and provides the respective signals to the voice switch 2 and the DSLAM 4. The CO splitter 6 also combines the voice and data band signals received from the voice switch 2 and the DSLAM 4 and provides the combined signals to the copper loop 14.
The CO splitter 6 includes a low pass filter (LPF) 8 connected to the voice switch 2 and a high pass filter (HPF) 10 (or DC clocking capacitors) connected to the DSLAM 4. The LPF 8 filters out higher band xDSL signals and prevents such signals from interfering with the voice switch 2. Likewise, the HPF 10 filters out low band voice signals and prevents such signals from interfering with the DSLAM 4. In other words, the high frequency signals generated by the DSLAM 4 will not interfere with the voice switch 2 because of the LPF 8, and the low frequency signals generated by the voice switch 2 will not interfere with the DSLAM 4 because of the HPF 10. The voice service typically occupies the band between 0 KHz (DC) to 4 KHz, and the xDSL service occupies some predetermined band above the voice service such as from 25.9 KHz to 1.1 MHz.
A signature S112 is also connected to the voice portion of the CO splitter 6. As known, the signature can be used in conjunction with a CO test system for fault identification and localization. The signature S112 is preferably a passive network such as a resistance, capacitor, zeners and diodes combined to from a unique network, which is used to assist in detecting fault conditions, loop length measurements, and the like. The signature S112 can also be active circuit elements that perform a specific function, as known in the art.
A second remote (RT) splitter 20 having a LPF 22, HPF 24, and signature SR 26 can be optionally installed in the customer""s premise. The LPF 22 is connected to the telephone 16 for filtering out high band signals, while the HPF 24 is connected to the ATU-R 18 for filtering out low band signals.
FIG. 2 illustrates a diagram of an existing circuit used in the conventional line sharing system as shown in FIG. 1. The LPF 8 generally includes series inductors 30-35 and capacitors 42, 44, while the HPF 10 generally includes series capacitors 50-53 and inductors 60, 62.
The voice switch 2 typically includes circuitry for interfacing with a pair of wires, tip and ring, from the outside plant. As is well known, tip and ring are terms used to describe the two wires that are used to set up a telephony/xDSL connection. The voice switch 2 includes amplifiers 73, 74, connected in series to resistors 71, 72, respectively. The amplifiers 73, 74, and resistors 71, 72, form a balance drive interface circuit to the tip and ring wires. As known, the voice switch 2 can be implemented with transformers instead of amplifiers 73, 74. The DSLAM 4 includes a pair of capacitors 81, 82 connected in parallel.
With the conventional line sharing system and CO splitter 6 as shown in FIGS. 1-2, the ILEC using the voice switch 2 can continue to test and maintain the copper loop in the traditional manner, typically using mechanized loop testing via a Class 5 switch. The LPF 8 in the CO splitter 6 does not significantly interfere with this process. However, it is well known that the CLEC""s ability to test and maintain the copper loop for xDSL service is greatly handicapped using the conventional CO splitter 6 because of the HPF 10 and the POTS service. Thus, it is very difficult for the CLEC to access the copper loop for independent testing and maintenance.
Another disadvantage using the conventional system and method is that the CO splitter 6 is typically implemented in a manner that benefits the ILECs, which utilize their customized test systems to test and maintain the POTS portion of the copper loop. The CLECs, which are typically in direct competition with the ILECs for xDSL service, currently do not have a system and method for independent testing/maintenance of the copper loop. For example, when the ILEC uses the copper loop for voice service, the CLEC is generally prohibited from testing the copper loop in fear of disturbing or interfering with the voice service. If the copper loop is busy or off-hook (i.e., customer using the telephone), the CLEC will be very hesitant to test the copper loop because such testing may terminate the telephone call.
As described above, the conventional CO splitter is generally acceptable for the ILECs for testing the copper loop for voice service, but it is inadequate for the CLECs for testing the same loop for xDSL service. Accordingly, there is a need for a system and method for providing a reliable and effective manner of testing and maintaining the copper loop in the xDSL environment for CLECs. Thus, there is a need for a remotely actuated splitter bypass system and method for improved testing and maintenance of the copper loop for the CLECs without interference or disturbance to/from the POTS service.
In view of the above-described problems of the prior art, it is an object of the present invention to provide a remotely actuated splitter bypass system and method.
It is another object of the present invention to provide a system and method for implementing a remotely actuated splitter bypass function in the existing line sharing infrastructure for improved testing and maintenance for a CLEC.
It is yet another object of the present invention to provide circuitry allowing a CLEC to access the copper loop for testing and maintenance with minimal interference and disturbance to/from the POTS service.
It is a further object of the present invention to provide a system and method for providing a reliable and effective manner for testing and maintaining a copper loop in the xDSL environment for a CLEC.
It is still a further object of the present invention to provide a system and method for remotely actuating a bypass function in a splitter such that testing and maintenance can be performed by a CLEC without interference or disturbance to/from the POTS service.
It is another object of the present invention to provide controls signals that are carried by the same copper loop pair during testing.
It is yet another object of the present invention to provide an enable signal to enable multiple pairs of copper loops and when the enable signal is absent, all splitters automatically revert to the normal mode of operation.
It is a further object of the present invention for providing a method for remotely actuating a bypass function in a splitter using a direct control approach.
It is yet another object of the present invention for providing a method for remotely actuating a bypass function in a splitter using a state machine control approach.
These and other objects of the present invention are obtained by providing a remotely actuated splitter bypass (RASB) function that can be used with a conventional splitter in the current line sharing system. The RASB includes circuitry, working in conjunction with an off-the-shelf splitter, for testing and maintaining a copper loop by a CLEC with minimal interference and disturbance to/from the POTS service. The splitter bypass operation includes the steps of selecting a copper loop pair for testing, actuating a first relay for monitor mode, actuating a second relay for bypass mode, testing the selected copper loop, and resetting the first and second relays back to normal mode. The RASB can be implemented using direct control or state machine control.